Spark plug



Jan. 13. 1925.` 1,522,929

A. WILLIAMS SPARK PLUG Filed June 2l, 1922 f ,/l. WzZZZz'amS Patenteddan. 13, 192.53.

*Murrina .STATES AMO'S WIL'LAMS; OF

1522,92@ Farrar orties.

'SPARK Proef.

appncaeon nfiiu time la1,

T0 all 'whom t may concern.'

Beit lenow/n 'lthat Ir, Aires lVfrLLrAars, citizen of the United States, residing Lat East Toledo, in fthe-county o-Luoas and State of Ohio, have invented certain new and 'useiiul Improvements in Spark Plugs, of which the following is a specification.

This invention relates .to fan improved spark plug and seeks, as one of its :principal objects, to provide' a :plugr wherein .the gap surfacesfof the lelectrodes may be readily cleaned Without removing fthe .plug from an engine cylinder. V Y A V The invention has `as ai further fobziect to provide a` plug embodying a visible gap whereby .the `ftunctioning of tliewplug: may be readily ascertained gat any time.

`And the invention has as a' still further object to provide a plug which w-ifllbeclraracteriaed iby Aextreme structural simplicity and which will be well adapted for use ifn connectionv `with any A.conventional make 4oi inter/nal combustion engine.

AOther and incidental vobjects will ap-pear hereinafter.

In the drawing:

Figure 1 isa side eleva-tion of my improved sparlrplu'g; Y

Figure 2 is a vertical'sectional v-iewtaken medially through the device.

VFigure 3 is a transverse sectionalview on the line S-iof Figure 1, looking in the direction of the arrows, and

Figure 4 is a fragmentary elevatioirsliowing a slightly different embodiment of the invention.

In carrying the invention into eect, I employ a shell 10 threaded at its lower end for engagement in the usual spark plug opening of an engine cylinder and depending from the lower end edge of the shell are oppositely disposed ground electrodes 11 eX- tending toward each other beneath the shell.

Removably fitting in the shell is an insulator 12 which may be of porcelain or other approved material and surrounding the insulator is a nut 13 threaded into the shell for clamping the insulator in position. Mounted upon the insulator at its upper end is a metal band 14 crimped at its lower margin into a surface groove in the insulator and slidably litt-ing through the insulator axially thereof is a central electrode 15. At its lower end this electrode is provided with a disc 16 and at a point spaced above the disc with a collar 17 confronting the lower 19a-a. Tseran ive.` 569,894.

lar 17 iafnd the insulatoiwto form a closed lio'intfbetween the centralelectrode 'and the insulator. A fgasket 20 of suitable insulare ing'mateiira-l ism-ranged between' the lower end olf the .spring and' the" insulator Vand iixe'd'itothe velectrode 15 'at its upper end is afdie'lectric knob 21,'5Jthis knob abutting Vthe colla-r 19.

Formed in the 4insillator 12"near its u pper endii's, as showin iai detail in Figure "3, 4an opening 22 intersecting the centra'l electrode 15 and 'intersecting saidj'opening `at substantiallly right ang-les theretoV is a somewhat larger sight opening '23. Registering with the latter opening is* an opening 24 in the wfall oit :theband and lconiied between the band and the insulator is a transparency 25 closing. the sight opening. Threaded through the wa'l-l of' the fbandto extend into the opening. .22'fi's an electrode 26" cooperating `with "the central electrode to form a sparlrgap therebetween and', lof course, the electrode @emay be adjusted upon the band for varying the length of said gap. Threaded upon said elect-rode is a locking nut 27 abutting the band and confronting said nut is a binding nut 28 upon the electrode for Securing a circuit wire thereto. Thus, when a circuit is closed through said wire, current will flow through the electrode 26 to jump the gap between said electrode and the electrode 15 when the current will low thro-ugh the electrode 15 to jump the gaps between the disc 16 of the latter electrode and the ground electrodes 11. As will be appreciated, the presence of the gap between the electrodes 15 and 26 will tend to insure the functioning of the plug at the gaps between the disc 16 and the ground electrodes and, of course, the spark occurring at the formergap will be readily visible through the sight opening 23. Accordingly, the operation oi the plug` may be readily observed at any time.. Should the plug become fouled, the

may properly function. I accordingly pro-o vide a plug wherein the troubles incident to fouling may be overcome with a minimumV ofy difliculty.

`;In some instances, I may desire to provide the plug with an external gap for short eircuiting the plug when fouled so that the spark at'said gap may visibly indicate the ineflicient condition ofthe plug. In such .instance, I form the band '14 at one side Y thereof with a depending linger 29 extending downwardly along the insulator toward the nut 13 and providing an electrode terminating adjacent the nut forming a spark gap therebetween. Thus, when the disc 16 of the central electrode and the ground electrodes 11 become fouled so as to hinder the jumping of the current from said disc tor-the ground electrodes, the current will, following the course of least resistance, flow through the linger 29 to jump the gap between said linger and the nut 13. vThe spark occurring at said gap will thus serve to apprise` the operator of the condition of the plug and since the gap 1s exposed, sparking at the gap will be readily visible.`

In Figure 4 of the drawing, I have illustrated a slightly different embodiment of the invention wherein the insulatorV of the plug is indicated at 29, the band at Vthe upper end of the insulator at 30, the central electrode at 31, and the cooperating electrode upon the band 30 at 32, these parts corresponding to similar, partsof the preferred construction. However, in the present instance, the finger upon the band 30,

as illustrated in the preferred construction,

,is eliminated, the external gappformed by said finger heilig omitted. Otherwise, 'this l. A spark .plug including a shell, anin- Y sulator carried thereby, a central electrode mounted upon the insulator, a band carried by the insulator, and an electro-de mounted upon said band to cooperatewith the central electrode forming a spark gap therebetween, the band being provided with a l finger extending toward Vthe shell and forming a visible indicating spark gap. between Ysuoli electrode'and the shell. A

2. -In -a spark plug, cofacting electrodes forming-an ignition spark gap, and aV third electrode in shunt with onelofsaid rst mentioned electrodes and forming an indicator spark gap of greater resistance than said first mentioned gap. v

3. In a spark plug, coacting electrodes forming an ignition spark gap, anda third electrode at t-he exterior of the plug inl shunt with one of said first mentioned-elec; trodes and forming a visible indicatorspark gap of greater rresistance than said first.

mentioned gap. Y Y

4:. In a spark plugincluding a shell, coacting electrodes forming an ignition spark gap, and Va. thirdelectrode in shunt with one of said first mentioned electrodes and cooperating with the shellto form an'indicator spark gapof greater resistance than said first mentioned gap. f

In testimony whereof I AMOS WILLIAMS. [1.. s] Y affix myV signature. 

